1. Field of the Invention
The present invention relates to a throttle assembly for intake air. More specifically, the present invention relates to a throttle assembly for intake air, which includes a plurality of throttle devices for injecting fuel into intake air to generate air-fuel mixture and a power transmission mechanism for connecting drivingly driving portions of the throttle devices with each other and a V-type engine therewith.
2. Description of the Prior Art
Japanese Patent Application Laid-Open No. 2004-239234 discloses a V-type engine including a power transmission mechanism such as a link mechanism for connecting throttle devices with each other. The link mechanism is accommodated in a link mechanism housing chamber defined by an outer wall member, whereby, the link mechanism is protected from stones, sand or dust. FIGS. 7, 8, and 9 show an example of a conventional V-type engine. In FIG. 7, the V-type engine includes first and second throttle devices 101 and 102 for supplying air-fuel mixture into cylinders of the engine respectively, and a link member (link mechanism) 115 for connecting drivingly driving portions of the throttle devices 101 and 102 with each other. The driving portions of the throttle devices 101 and 102 are, for example, constituted by throttle valve driving shafts 111 and 112 with swinging arms 113 and 114. Both the swinging arms 113 and 114 are connected by the link member 115 each other. Moreover, one swinging arm 113 is connected with one end of a cable device 120 as shown by an imaginary line. Other end of the cable device 120 is extended to a throttle operating portion of a throttle grip 121 and connected thereto. Whereby, the throttle devices 101 and 102 can be operated by the same amount of rotation at the same time.
The link member 115 and the swinging arms 113 and 114 are accommodated in a link mechanism housing chamber 110 surrounded by a link case 103 coupled to throttle bodies of the throttle devices 101 and 102 and a case cover 104 as shown in FIG. 8.
As shown in FIG. 9, in the cable device 120, an end male thread portion 127 of an outer cable 120b of the cable device 120 is fitted into a groove or notch 123 formed in a front wall of the link case 103, a pair of nuts 124 and 125 are threaded to the end male thread portion 121, the front wall of the link case 103 is sandwiched between the nuts 124 and 125 from front and rear of the link case 103, and the outer cable 120b is fixed to the link case 103. As shown in FIG. 7, a drain hole 130 for discharging water or the like in the link mechanism housing chamber 110 is formed in a lower wall of the link case 103.
The link case 103 and the case cover 104 shown in FIGS. 7 to 9 mainly protect the link member 115 from a stone, sand, or dust. The link case 103 and the case cover 104 do not include any special configuration for preventing the entry of water and mud into the link mechanism housing chamber 110.
As shown in FIGS. 7 to 9, in the V-type engine allowing the entry of water and mud into the link mechanism housing chamber 110, in the event that water and mud adhere to the movable portions of the link member 115, e.g., the rotating and coupling portions at the front and rear ends of the link member 115 or that mud is accumulated near the swinging arm 114 on the rear side of the link member 115, rust can occur or the operation of the link member 115 and the swinging arm 114 can be failed. In many cases, the V-type engine mounted on a four wheeled vehicle for irregular ground, which runs on a field, sandy beach, or rough ground is driven in an environment in which it suffers from water and mud together with a stone or sand or the like. The link mechanism housing chamber 110 is strongly required to prevent water and mud.